Despite recent research on the impact of disability on function, little information is available to evaluate the need for daily support in persons with Down syndrome. The aim of this study was to evaluate the prevalence and relative degree of difficulty experienced by this population in routine hygiene and health care when compared to their siblings. A proxy French language questionnaire was used for this cross-sectional survey of 199 persons with Down syndrome and 153 siblings (mean age 12.3 years, range < or = 1-48). Individuals in the study group had significantly more difficulty performing all activities related to routine hygiene and health care, and were 2-22 times more likely to need help than the control group. Certain acts of routine health care were performed more regularly by those in the study group (6/12 items), and specialist medical and paramedical visits were more regular (OR = 7-44). Increased difficulty and need for help in performing acts of basic self-care may reduce autonomy and social integration for persons with Down syndrome. Recommendations are made in relation to the training of caregivers and health professionals.